The present invention is directed to systems and methods useful in testing for occult blood in a fecal specimen. More particularly, the invention is directed to a testing apparatus which is suitable for at-home use by untrained individuals, as well as by clinicians in hospitals and doctor offices.
Over 140,000 new persons per year in the United States are afflicted with cancer of the colon and rectum, the disease occurring equally in both men and women. Contrary to many other forms of cancer, early diagnosis and treatment of colorectal cancer and its precursor polyps does result in a cure rate of 80% to 90%. If, however, the disease is not detected until the later stages, the cure rate drops significantly. Thus, early detection of the disease is important to successful treatment of colorectal cancer. For this reason, it is recommended that all individuals over age 50 with no family history of the disease be screened annually for colorectal cancers. Individuals with family history of the disease or other known risk factors should be screened annually beginning no later than age 40.
Conventional screening procedures consist of testing for occult (hidden) blood in stool samples provided by a patient. Typically, the patient must collect two separate specimens on a test card on each of three consecutive days, and then deliver the test cards to a laboratory. At the laboratory, a physician or lab technician applies developer liquid to each specimen's test matrix, which has previously been impregnated with a suitable chromogenic reagent, such as guaiac. If blood is present in the specimen, the chromogenic reagent will cause the test matrix to change colors when the developer fluid is added, indicating that fecal occult blood or a similar reactant has been found.
One factor deterring individuals from undergoing their recommended annual screening is the natural revulsion which many, if not most, people feel toward handling and looking at fecal matter. This revulsion may be amplified by the lack of a suitable implement for obtaining a specimen and applying it to the test matrix. Most test kits simply provide a wooden coffee-stirrer type stick which is somewhat difficult to manipulate and often, because of its generally smooth exterior surface, does not pick up a large enough sample or retain the sample without risk of dropping some of the fecal matter. Another unpleasant factor is the inconvenience and, sometimes, embarrassment associated with transporting or mailing the fecal matter specimens to a testing laboratory in a paper envelope.
In order to eliminate or reduce the aforementioned problems, various attempts have been made to develop a convenient test kit which requires a minimum of handling of fecal specimens, and can be performed by an untrained individual in the privacy of his or her own home. Examples of such attempts are disclosed in U.S. Pat. Nos. 4,582,685 and 5,196,167 to Guadagno et al., and U.S. Pat. No. 5,840,584 to Waldenburg. None of these prior art test kits have successfully met all of the needs of in-home users, however, and none has been approved by the FDA for over-the-counter sale.
To date, the only fecal occult blood testing kit which has been approved by for the FDA for over-the-counter sale is a kit manufactured by Diagnostica, Inc., of Las Vegas, Nev., features of which are disclosed in U.S. patent application Ser. No. 09/132,439 and International Application No. PCT/US99/17954. The Diagnostica kit comprises a container of free-standing developing medium, and a test matrix having a specimen placement area on one side. On the opposite side of the test matrix is a result area that generally coincides with the specimen placement area, and a control area that is longitudinally spaced from the result area. Both the container and the matrix are encased in a housing having a first pair of openings aligned with the specimen placement area, a second pair of openings aligned with the result area, and a third pair of openings aligned with the control area. A cover is provided for securely enclosing a specimen located on the specimen placement area. To test for occult blood, a user simply places fecal specimens in the openings aligned with the specimen placement area, closes the cover, compresses the housing to break the container and releases the developing medium. He or she then turns the housing over to look for appropriate color changes in the result and control areas.
The aforementioned Diagnostica test kit possesses numerous advantages over the prior art. The cover is particularly advantageous, since it keeps the fecal specimen out of the user's sight and prevents it from dropping off of leaking from the specimen placement area, even when the user inverts the housing to read the results. In addition, the kit can be disposed of easily and hygienically after testing, with no need for special handling.
Nonetheless, the Diagnostica kit disclosed in the aforementioned U.S. and International patent applications has some potential drawbacks. Users who have not performed the test before may have difficulty understanding or remembering the instructions and may perform the steps in the wrong order. In addition, some users may collect too little or too much sample on the stick provided with the kit, and have difficulty spreading it over the specimen placement area. Still others may find it difficult to open and close the cover of the housing with one hand while holding the specimen collection stick in the other hand.
Accordingly, it would be advantageous to provide an apparatus for testing for occult blood, for example, fecal occult blood, with features that enhance its ease of use by untrained individuals. Further, it would be advantageous to provide a hygienic and relatively simple test kit which reduces the need for manual dexterity, while providing accurate and reliable results.